Expanded extrudates from corn starch-lamb blends: process optimization using response surface methodology

A central composite second-order design was used to study the effects of feed (raw material blend) moisture, process temperature, and screw speed on expansion ratio (ER) and shear-force (SF) of extrudates from blends of corn starch and lean lamb. Quadratic polynomial equations were obtained by multiple regression analysis using response surface methodology. The predicted models were adequate when tested by the lack of fit and coefficient of determination. The validity of the models was also confirmed by experimental data. Regression analysis predicted an optimal (minimal) SF to be attained with 26.5% feed moisture, 148°C process temperature, and 134 rpm screw speed. This process condition was used in a companion study to produce and compare extrudates from blends of corn starch and lamb or mutton with similar extrudates produced with other meats. ©